Lecture 15: Cryosphere Part 1 Flashcards
-Components of the Cryosphere -Permafrost and Periglacial Landscapes -Sea Ice -Glaciers (37 cards)
What is the Cryosphere?
Encompasses the parts of the Earth where water freezes for at least part of the year, or remains perennially frozen.
-The frozen water part of the Earth’s system
What is albedo?
Fraction of light that is reflected by a body or surface.
-Snow has a high albedo
What are the four components of the Cryosphere? (that we are studied in class)
- Snow
- Permafrost
- Sea ice
- Glaciers
What is an annual snowline?
Marks the boundary of areas that have snow year-round with those that don’t.
What controls the shape and size of the snowline?
-winter snow accumulation and summer melting
How does the elevation of the snowline correlate to temperature?
- Lower in polar areas where temperature is colder
- Lower in coastal areas where there is more moisture
What is permafrost and what does it store?
Ground (sediment or rock) that remains frozen for 2 or more years.
-stores a lot of carbon because it freezes organic matter- preventing it from rotting
What is the active layer?
The surface layer of the frozen sediment or rock that thaws seasonally.
How does an ice wedge form?
In the fall/early winter, the ground can get very cold and contracts, which causes it to crack.
- Snow blows into this crack and seasonal melt allows water to fill it.
- Then it refreezes during the next winter, as the ice expands which causes a wedge to open in the ground. An ice wedge is the result of this processes repeating
-Oldest ice in the northern hemisphere
How are solifluction lobes formed?
They are formed by downslope creep of the active layer when it is saturated.
What is a patterned ground?
geometric patterns that form on surfaces experiencing intense freezing and thawing.
-e.g. Polygonal ground formed by ice wedges
How does sea ice form?
- Air temperature falls below freezing point of seawater
- Initially small needles of ice form, frazil ice
- Eventually freeze together and form continuous ice cover
What are the two kinds of sea ice?
- Pancake ice
2. Nilas
Where do pancake ice form?
Rough water
Where do nilas form?
Smooth water
Where do we find sea ice?
- Antarctic
- Arctic
What is the sea ice like in the Antarctic?
Surrounds the continent, is largely seasonal
What is the sea ice like in the Arctic?
Is an ocean covered in sea ice, extends into the Bering Sea, has perennial ice.
What is polar amplification?
Northern latitudes experiencing much greater warming
-one reason is due to loss of sea ice (Arctic)
Why is sea ice an important component of the Earth’s system?
- Increases surface albedo
- Insulates the ocean from heat loss or gain
- Provides a barrier to exchanges between ocean and atmosphere
- Salt ejected by growing sea ice alters the density of water and helps drive ocean circulation
- A major component of polar ecosystems
- Arctic sea ice, covering the Arctic ocean, is particularly sensitive to climate change and connected to global climate
How does sea ice affect the ocean circulation?
As sea ice freezes, salt is ejected making the surface ocean water saltier. This cold and salty water is denser and sinks into the deep ocean basins, which drives deep ocean circulation.
-(AABW) Antarctic Bottom Water
-(NADW) North Atlantic Deep Water
As the Arctic sea ice shrinks, ocean waters becomes less salty and warmer, thus less dense, slowing the NADW
How does sea ice affect the atmosphere?
- Sea ice isolates the ocean from the atmosphere, cutting off heat exchange.
- Sea ice also reflects light and heat
- Contributes to the coldness of polar regions, helping produce a steep temperature gradient between the equator and the poles, which drives atmospheric circulation
What is a glacier?
Land-based mass that flows.
How does it flow?
From high elevations to low elevations.
